User Manual

Multichannel Monitoring Tutorial Booklet (M2TB) rev. 3.5.2

Masataka Nakahara : SONA Corporation

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3-8-4. Speaker placement height and time alignment

If delay compensation is to be applied in an environment in which all of the speakers are not placed at the

identical height, we must consider how this will interact with the playback sound field and the playback response.

[Fig. 34] shows how the height of the surround speakers is related to the monitoring distance. In example

“A” all speakers are placed at the same height. Examples “B” and “C” place the surround speakers higher

than the front speakers. “B” shows the surround speakers placed closer to the listening point (as seen in

the horizontal plane) in order to make the monitoring distance identical to the other speakers. “C” shows

the surround speakers placed at the same distance as the other speakers (in the horizontal plane), resulting

in a longer monitoring distance for the surround speakers.

[Fig. 34] Heights of the loudspeakers and time alignment

In the case of “A”:

playback response, surround sound field

Since all speakers are placed at equal distances in the horizontal plane, the surround playback sound field

is a perfect circle, which is ideal. Since the actual distance from each speaker to the listening point is

identical, there is no danger that comb filtering or the Haas effect will occur between channels, and the

playback frequency response is also good.

In the case of “B”:

playback response, surround sound field

Since the actual distance from each speaker to the listening point is identical, there is no danger that comb

filtering or the Haas effect will occur between channels, and the playback frequency response is also good.

However in the horizontal plane, the surround speakers are closer, meaning that the surround sound field is

not a perfect circle. Naturalness of the surround playback field is obtained when the distance from each

speaker to the listening point is the same in the horizontal plane. In such cases, the perceptual impression

will be that the surround sound is being played back from a nearby but higher location, and the surround

playback will be lacking in depth. If the surround is more distant than the front it will seldom be perceived

as being unnatural, but if it is closer, the listener will usually sense that something is wrong. Sometimes this

type of sound field can be created by automatically adjusted delay compensation, so caution is needed.

In the case of “C”:

playback response, surround sound field

Since equal distance in the horizontal plane is maintained, the surround sound field is a perfect circle,

which is good. On the other hand, the actual distance from the surround speakers to the listening point is

greater than the distance to the front speakers, possibly causing problems with the playback response. For

example if the same type of signal is being played back from the front channels and the surround channels,

LS,RS

L,C,R

LS,RS

L,C,R

LS,RS

L,C,R

ABC

: Best

: Good

: Not Bad